Biology: ATP and Polynucleotide Formation

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Questions and Answers

What is the function of tRNA during translation?

To transcribe the mRNA from DNA

To carry specific amino acids to the ribosome (correct)

To ensure codon-ant codon pairing is accurate (correct)

To provide energy for the translation process

During translation, how does the ribosome facilitate peptide bond formation?

By exposing six bases of mRNA at a time

By catalyzing the reaction with peptidyl transferase (correct)

By directly synthesizing amino acids

By binding to the mRNA at multiple sites

What role do codons play in mRNA?

They facilitate the movement of ribosomes

They sequence amino acids in a polypeptide (correct)

They determine the lifespan of mRNA

They pair with DNA during transcription

What is the significance of UAA during the translation process?

It is a stop codon that signals termination of translation Signup and view all the answers

How does mRNA differ in lifespan compared to tRNA during protein synthesis?

mRNA is short-lived, producing proteins for brief periods Signup and view all the answers

How can multiple ribosomes work on the same mRNA strand simultaneously?

Polyribosomes form from multiple ribosomes translating one mRNA strand Signup and view all the answers

What is required for the specific pairing of tRNA an mRNA?

Complementary base pairing according to codon-anticodon relationships Signup and view all the answers

Which type of RNA is responsible for forming a copy of the DNA code?

mRNA Signup and view all the answers

What is the main function of tRNA in protein synthesis?

To carry amino acids to the ribosomes Signup and view all the answers

During the transcription process, which base pairs with adenine in RNA?

Uracil Signup and view all the answers

What initiates the formation of mRNA from DNA?

RNA polymerase Signup and view all the answers

What is the role of codons in the genetic code?

To specify amino acids Signup and view all the answers

In which order does the process of protein synthesis occur?

Transcription followed by Translation Signup and view all the answers

Where does transcription take place within the cell?

Nucleus Signup and view all the answers

Which property describes the codons in the genetic code?

Degenerate Signup and view all the answers

Which amino acid is coded for by the codon GAA?

Leucine Signup and view all the answers

What is a key structural difference between RNA and tRNA?

tRNA has an amino acid binding site while RNA does not Signup and view all the answers

During transcription, which molecule is synthesized?

mRNA Signup and view all the answers

Which component is not involved in the process of translation?

RNA polymerase Signup and view all the answers

What step directly follows mRNA pairing with ribosomes in the translation process?

tRNA attaches to the mRNA strand Signup and view all the answers

What is the main purpose of codons in mRNA?

To code for amino acids Signup and view all the answers

Where does translation occur within a cell?

Cytoplasm Signup and view all the answers

What role do anticodons play in translation?

They pair with corresponding codons on mRNA Signup and view all the answers

How are proteins processed after their synthesis?

They are modified in the rough endoplasmic reticulum Signup and view all the answers

Which of the following is not a step in protein synthesis?

Replication of DNA Signup and view all the answers

What characteristic of ATP allows it to easily diffuse between cell organelles?

It is small and water soluble. Signup and view all the answers

Which process is NOT a use of ATP in cellular functions?

Photosynthesis Signup and view all the answers

How do the two polynucleotide strands of DNA maintain their stability?

By hydrogen bonding between bases. Signup and view all the answers

What is the significance of the phosphodiester bond in polynucleotide formation?

It links together nucleotide's sugar and phosphate. Signup and view all the answers

Which feature of DNA structure contributes to its double helix shape?

The anti-parallel orientation of the strands. Signup and view all the answers

Study Notes

Molecules, Diet, Transport and Health

ATP is a phosphorylated mononucleotide made from ribose, adenine, and phosphate groups.
ATP is a universal energy currency in cells, easily diffusing between organelles due to its small size and water solubility.
ATP provides immediate energy by breaking down into ADP and releasing energy in the presence of water.
ATP is crucial for many cellular processes, such as cell division, muscle contraction, maintaining body temperature, protein synthesis, and nerve impulse transmission.

Polynucleotide Formation

Polynucleotides form during interphase.
Condensation reactions link nucleotides, creating a phosphodiester bond between the 5' carbon of one nucleotide and the 3' carbon of the next.
The sugar-phosphate backbone forms the structural framework of DNA and RNA, with nitrogenous bases projecting outwards.
Nucleotides align in an antiparallel configuration (3' to 5' and 5' to 3').
Hydrogen bonds form between complementary bases (A=T, G=C).
A double helix structure is formed by the two strands twisting.
Each full turn in the DNA molecule contains 10 base pairs, spanning 3.4 nm.

DNA Replication (Semi-conservative)

DNA replication is semi-conservative.
Each new DNA molecule contains one original and one newly synthesized strand.
The original DNA strand serves as a template for the new strand.
DNA helicase unwinds the DNA double helix, breaking hydrogen bonds between complementary bases.
Free activated nucleotides line up along both strands.
DNA polymerase adds nucleotides complementary to the template strand.
DNA ligase seals the gaps between the segments, finalizing the new DNA strands.
The process occurs during the S phase of the cell cycle.

DNA Replication Experimental Evidence (Meselson-Stahl)

Bacteria were grown in a medium containing heavy nitrogen (15N).
After one generation, DNA molecules were intermediate weight (hybrid).
After two generations, DNA molecules were of light weight (fully replicated).
This outcome confirmed semi-conservative replication.

Genetic Code

A gene is a segment of DNA containing a specific sequence of bases, coding for a specific protein sequence.
The three-base sequence on DNA is called a codon.
There are 64 possible codons, sufficient for specifying 20 amino acids.
The genetic code is universal (same codons specify the same amino acids across all living organisms.)
The genetic code is degenerate (multiple codons can specify the same amino acid). This degeneracy in the genetic code minimizes the effect of mutations.

Protein Synthesis

This involves two stages : transcription and translation.
Transcription creates a messenger RNA (mRNA) copy of a gene's DNA sequences in the nucleus.
Translation takes place in the cytoplasm. mRNA binds to ribosomes, which translate the mRNA sequence into a specific chain of amino acids (a protein).
Transfer RNA (tRNA) molecules carry specific amino acids to the ribosome, aligning them according to the corresponding mRNA codons.
A peptide bond forms between adjacent amino acids.
Newly synthesized proteins may undergo modifications (e.g., glycosylation) within the endoplasmic reticulum.
Proteins are transported out of the cell in vesicles.

RNA Types Involved in Protein Synthesis

mRNA carries the genetic code from the DNA to the ribosome.
tRNA molecules bring specific amino acids to the ribosome.

Ribosomes

Ribosomes are responsible for assembling amino acids into a polypeptide chain according to the mRNA sequence.
Ribosomes are composed of ribosomal RNA (rRNA) and proteins.
Ribosomes have a small and a large subunit.

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Description

Explore the critical roles of ATP in cellular processes such as energy provision, cell division, and muscle contraction. Also, learn about the formation of polynucleotides and the structural framework of DNA and RNA through condensation reactions and phosphodiester bonds.